package com.swl.util;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.Random;

/**
 * 用于生成图片，使用swing的方式
 */
/*
 * 验证码图片生成方法
 * */
public class VerifyCode {
    private int w = 70;
    private int h = 35;
    private Random r = new Random();
    //可选的字体
    private String[] fontNames = {"宋体","华文楷体","黑体","微软雅黑","楷体_GB2312"};
    //可选的字符
    private String codes = "0123456789abcdefghijklmnopqrstuvwsyzABCDEFGHIJKLMNOPQRSTUVWSYX";
    private Color bgColor = new Color(255,255,255);
    private String text; //图片中显示的验证码

    //生成随机的颜色
    private Color randomColor() {
        int red = r.nextInt(255);
        int green = r.nextInt(255);
        int blue = r.nextInt(255);
        return new Color(red,green,blue);
    }

    //生成随机字体
    private Font randomFont() {
        int index = r.nextInt(fontNames.length); //随机生成字体的下标 [0-4]
        String fontName = fontNames[index];//生成随机的字体名称
        int style = r.nextInt(4);//生成随机的样式，0（无样式），1（粗体），2（斜体），3（粗体加斜体）
        int size = r.nextInt(5)+25;//生成随机字号25-29
        return new Font(fontName,style,size);
    }

    //画干扰线
    private void drawLine(BufferedImage image) {
        int num = r.nextInt(6)+2;
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        for (int i = 0; i < num; i++) {//生成两个点的坐标，即4个值
            int x1 = r.nextInt(w);
            int y1 = r.nextInt(h);
            int x2 = r.nextInt(w);
            int y2 = r.nextInt(h);
            g2.setStroke(new BasicStroke(1.5F));
            g2.setColor(randomColor());//干扰线是随机的颜色
            g2.drawLine(x1,y1,x2,y2);//画线
        }
    }

    //生成随机一个字符
    private char randomChar() {
        int index = r.nextInt(codes.length());
        return codes.charAt(index);
    }

    //创建一个BufferedImage
    private BufferedImage creatImage() {
        BufferedImage image = new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = (Graphics2D) image.getGraphics();
        g2.setColor(this.bgColor);
        g2.fillRect(0,0,w,h);
        return image;
    }

    //调用这个方法得到验证码图片
    public BufferedImage getImage() {
        BufferedImage image = creatImage(); //创建图片缓冲区
        Graphics2D g2 = (Graphics2D) image.getGraphics();//得到绘制环境
        StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本
        for (int i = 0; i <4 ; i++) {//循环四次，每次随机生成一个字符
            String s = randomChar()+"";//随机生成一个字符
            sb.append(s);//把字母添加到sb中
            float x = i * 1.0F * w / 4;//设置当前字符的x轴坐标
            g2.setFont(randomFont());//设置随机字体
            g2.setColor(randomColor());//设置随机颜色
            g2.drawString(s,x,h-5);//画图
        }
        this.text = sb.toString();//把生成的字符串赋给了this.text
        drawLine(image);//添加干扰线
        return image;
    }
    //返回验证码图片上的文本
    public String getText() {
        return text;
    }
    //保存图片到指定的输出流
    public static void output(BufferedImage image, OutputStream out)
            throws Exception{
        ImageIO.write(image,"PNG",out);
    }
}
